make border and background for amc grades like this:

steps:
1- in the head, add the code:

\usepackage{xcolor}
\newcommand{\mybox}{\fcolorbox{white!100}{white!100}}

2- in the docum, let any Qs like:

\mybox{\framebox(77,13){
\begin{question}{33}
\begin{choicescustom}
\wrongchoice[أ]{}%
\wrongchoice[ب]{}%
\wrongchoice[ج]{}%
\wrongchoice[د]{}%
\end{choicescustom}
\end{question}
\vspace{-0.05cm}
}}\vspace{-0.13cm}

you can change the dimentions (77,13) , if you change the choices number.

regards